This invention relates to a throttle trimming device operable by the vacuum in the fuel intake system.
In internal combustion engines, vacuum conditions vary considerably in the fuel intake manifold at different phases of vehicle operation. That is for example when the throttle is depressed rather fast such as during initial acceleration or during any fast or hard acceleration, a lower vacuum condition will exist in the intake manifold than when the engine is in steady operation or during deceleration. In many operating conditions of the vehicle such as in conditions wherein the vacuum in the intake manifold is at higher values, it is easy for the operator to over-throttle since under such conditions excess depression of the accelerator pedal does not produce any greater power and the operator cannot feel this. Fuel is obviously wasted under such conditions. Also in the higher vacuum conditions such as in freeway driving the operator must raise and lower the pedal repeatedly according to the grade in the road and thus upon each down movement of the pedal, there is the possibility of over-throttling. Not only is fuel wasted in over-throttling but engine emissions are increased.